Thermoregulation

• Thermoregulation

  • Body temp changes affect structure and globular proteins activity (e.g. enzymes)
  • Endotherms (e.g. mammals and birds)
  • Can use internal heat source from metabolism to maintain body temp
  • Maintain constant temperature in narrow limits by both physiological and behavioural methods
  • Ectotherms (All animals, except birds and mammals)
  • Obtain body heat from external environment
  • Do not generate much in body
  • Use behavioural mechanisms to control temperature
• Thermoregulation in Endotherms

  • Advantages:
  • Maintain constant temperature
  • Activity possible regardless
  • Can inhabitant colder areas
  • Disadvantages:
  • Significant energy intake used for warmth
  • More food needed
  • Less for growth
  • Sweating:
  • Sweat evaporates off our skin, cooling
  • Energy to evaporate it (latent heat of vaporisation) is internally
  • Mammals
  • Hypothalamus at brain base
  • Temperature receptors monitor blood temp
  • Also impulses from peripheral skin temp receptors
  • Indicates external environment; warning
  • Sends impulses to muscles and liver to control internal heat input
• Thermoregulation in Ectotherms

  • Advantages:
  • Use less food in respiration
  • Need to find less
  • Can survive for long periods without eating
  • More energy for growth
  • Disadvantages:
  • Less active in cooler temperatures
  • Need to warm up in morning to be active
  • Greater predation risk
  • May need energy stores to survive winter
• Endotherms Behavioural Mechanisms

  Too hot

  • Go to shade or hide in burrow
  • Orientate to decrease SA exposed to sun
  • In shade, spread limbs out to increase SA for heat loss by conduction and radiation
  • Remain inactive to reduce internal heat generation
  • Humans
  • Wear fewer clothes
  • Eat cool salads
  • Drink iced drinks

  Too cold

  • Move to warmer place, bask
  • Orientate to increase SA exposed to sun and radiation heat gain
  • In extreme, reduce SA by rolling into ball to reduce heat loss
  • Move about to generate muscle heat
  • Humans
  • Put on more clothes (insulation)
  • Eat hot food
  • Drink hot drinks
• Ectotherm Mechanisms

  Fill in

  A) More

  B) radiation/conduction

  C) Larger

  D) Less

  E) less

  F) Reduces

  G) rib cage

  H) Surface Area

  I) water

  
• Endotherms Physiological Mechanisms

  Fill in

  A) more

  B) relax

  C) Reduce

  D) More

  E) vasodilation

  F) more

  G) reduced

  H) Less

  I) increases

  J) Less

  K) contract

  L) Reduce

  M) vasoconstriction

  N) less

  O) increased

  P) more